A parka is supposed to look bulky, especially a down-filled parka. The feathers need space to do their job of insulating you from the cold. Therefore, a tight fitting down-filled parka defeats the purpose of the feathers because it squashes them together. Do not size down but rather wear an extra layer over the Tee.

Cedar panelled walls, cedar tiles, cedar shavings, cedar oil (if you can find it - it is banned in Canada). Rotate your clothes. Agitate yor clothing with your hand between the suits, running your hand up & down the garments. Moths don't like to be disturbed and hate cedar oil/wood. Keep window areas clean. Moth eggs can blow into your home with a breeze. That is all I can think of at the moment.